MSc

The investigation on "Characterization and hybridization in Nymphaea spp. " was undertaken in College of Agriculture, Padannakkad in the academic
year 2016-18 with the objective to study the morphology, reproductive biology
and to hybridize the seed forming Nymphaea sp. Based on the detailed survey in
Northern Kerala, fourteen accessions were collected, of which ten were
selected for detailed study. These consisted of two night blooming (Acc. 5 and
Acc. 6) and eight day blooming types. Based on flower colour variation, there
were accessions with different shades of pink (Acc.1, Acc. 2, Acc. 6, Acc. 9 and
Acc. 10), blue violet (Acc. 3 and Acc. 8), white (Acc. 4 and Acc. 5) and violet
(Acc.7).
Growth and development pattern of leaves and flowers were similar in all
the accessions. However, the ten accessions were distinct based on the leaf and
floral characters. The leaves in all the accessions were simple orbicular with subpeltate
lamina deeply cleft near to the petiole base. There was considerable
variability in the colour, margin and tip of leaf lamina. The biometric
characteristics of leaf such as length and width of lamina, length of petiole and
longevity of leaf showed variability among the accessions, with Acc. 2 showing
maximum length and longevity of the leaf.
Flowers were pedicellate and complete with all the floral whorls in a spiral
fashion on the floral axis. The process of opening and closing of flower repeated
for four consecutive days, except in Acc. 6 where it continued till fifth day.
Significant variation observed in flower morphology, anthesis and periodicity of
flowering in all accessions with critical difference between day and night
bloomers. The night blooming accessions showed superiority over day bloomers
in the flower bud characters viz., length and circumference of flower bud and
diameter of fully opened flower. The day bloomers differed from night bloomers
in having shorter stigmatic appendages and stamens with terminal appendages.
The night blooming accessions showed maximum duration for flower opening but
low frequency of flowering compared to day bloomers.
In general, all the accessions displayed strong protogyny except Acc. 5,
where the phases of stigma receptivity and anther dehiscence were found
overlapping. The pattern of anther dehiscence, duration of stigma receptivity and
fragrance were favoring cross pollination in day blooming accessions. The
adaptations such as overlapping of stigma receptivity and anther dehiscence in
Acc. 5, simultaneous dehiscence of all anthers and absence of fragrance in both
the night bloomers were pointing towards autogamy in these accessions.
Pollen grains of all the ten accessions showed regular staining with 1%
safranin. The in vitro pollen germination was maximum in 10% sucrose medium
with seven accessions (viz., Acc. 1, Acc. 3, Acc. 4, Acc. 5, Acc. 6, Acc. 7 and
Acc. 9) showing a remarkable increase in the pollen tube length.
Only five accessions (Acc.3, Acc. 4, Acc. 5, Acc. 6, and Acc. 7) produced
fruit and seeds in open condition with and without emasculation and no seed set
under protected condition. The germinability and speed of seed germination was
low without any treatments. Chemical scarification with different concentrations
of H2SO4, GA3 and Ethrel showed an enhancement in seed germination, with
maximum germination at a concentration of 100 ppm GA3 and 5% H2SO4.
Besides rhizome propagation, other methods like leaf proliferation (Acc. 1 and
Acc.7) and root tip proliferation (Acc. 5) were also observed. These alternative
modes of propagation showed earliness in the formation of leaf, root and flowers
compared to rhizome.
Hybridization among five seed forming accessions showed success only
among day bloomers (Ac. 3, Acc. 4 and Acc. 7) and with seed set in three crosses.
Only the seedlings of cross 1 (Acc. 4 x Acc. 3) established successfully and
produced flower within five months of seed germination. The initial evaluation of
the morphological characters of hybrid progeny showed similarity with either of
the parent for some characters. The colour of flower, color and shape of leaf were
intermediate to both the parents and number of petals, stamens and carpels were
unique to the hybrid progeny.